<?php
include '../../conn.php';
if(!isset($_GET['notice_id'])){
    $arr = [
        "desc" => "缺少参数"
    ];
    echo json_encode($arr);
    exit;
}
$sql = "select count(*) as num from users_comment
        where content_id = $_GET[notice_id]";
$req = $pdo->getOne($sql);
$arr = [
    "num" => $req['num']
];
echo json_encode($arr);